In that case Capture also must support better ways to keep the information in the MVR file updated, so exchange between multiple different apps is actually possible.
If you export to mvr out of Vectorworks, import into WYSIWYG, make a few changes and export from wyg to mvr again to import back into VW this is perfectly possible. If you replace wyg with Capture in the example above, the workflow is crippled and information is either not coming over or fixture associations (defining type and mode) have to be done over and over again.

Capture support MVR and i use it every time with success.

What I think is to Capture should support GDTF first, then MVR will be much accurate... 

That would not be possible as Capture develops its own library. There are many advantages in doing it this way (you'd have to ask @LarsWernlund for the specifics) It does not stand in the way of interchanging files though. In the MVR standard, each fixture has a unique identifier. 

A more streamlined way to not only import, but also export mvr files while maintaining the identifier and adding information in Capture to existing fixtures, is very welcome.